Abstract
Supercharging is very efficient to improve thermal efficiency and reduce emissions of diesel engines. Especially, electrical supercharger development has significantly progressed in recent years and it enables high supercharging pressure operation which could not be realized by conventional turbo engines. However, it is suggested that excessive supercharging has a negative impact on indicated thermal efficiency by zero-dimensional combustion simulation. In this study, verification experiments using a single cylinder test engine were carried out to confirm the decrease of thermal efficiency by excessive supercharging arise. Furthermore, the configuration of superchargers was investigated to realize the best excess air ratio condition on the test engine.
